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The Incidental Capture of Bats in Douglas-Fir Beetle Funnel Traps

NACFOR has been working with entomologist Darcie Quamme, Integrated Ecological Research and bat biologist Cori Lausen, Wildlife Conservation Society to raise awareness and develop solutions to prevent the incidental capture of bats in Douglas-fir bark beetle funnel traps. The project goals are to: 1) encourage stewardship and education on the ecological services provided by bats to the forest industry, 2) collect data on incidental bat captures, and 3) provide solutions to prevent capture.

In 2018 and 2019 NACFOR installed funnel traps in recently harvested cut blocks to monitor and control Douglas-fir bark beetle populations on the community forest. Over the two years, four pheromone baited traps captured seven Western long-eared bats (M. evotis), possibly attracted by the sound of beetles approaching the traps or live beetles in the traps. Bats were unable to escape due to the smooth surfaces/shape of the trap and detrimental effects of the insecticidal kill strip in the collection cup. A proposed solution to the incidental capture is to exclude bats from falling into the collection bucket a by placing fine-gauge wire mesh over the bottom funnel. This exclusion system will be tested in 2020. Reporting of live or dead bats in pheromone traps is valuable information for documenting and tracking occurrence of incidental capture. Reporting provides bat species information, capture timing and new information about prey species for bats.

A poster about the project was prepared by NACFOR’s biology intern, for distribution to forest practitioners and the bat community.

Click the thumbnail below to open the poster:

Checking a beetle funnel trap